616561511 has 4 divisors (see below), whose sum is σ = 636450624. Its totient is φ = 596672400.

The previous prime is 616561493. The next prime is 616561523. The reversal of 616561511 is 115165616.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 616561511 - 2¹⁰ = 616560487 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (616561111) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 9944510 + ... + 9944571.

It is an arithmetic number, because the mean of its divisors is an integer number (159112656).

Almost surely, 2^616561511 is an apocalyptic number.

616561511 is a deficient number, since it is larger than the sum of its proper divisors (19889113).

616561511 is a wasteful number, since it uses less digits than its factorization.

616561511 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 19889112.

The product of its digits is 5400, while the sum is 32.

The square root of 616561511 is about 24830.6566767776. The cubic root of 616561511 is about 851.1226278373.

It can be divided in two parts, 6165 and 61511, that added together give a palindrome (67676).

The spelling of 616561511 in words is "six hundred sixteen million, five hundred sixty-one thousand, five hundred eleven".